A fulvene-type compound as used herein is a compound containing a cyclopentadienyl-type group having an external carbon-carbon double bond bonding the cyclopentadienyl-type group to a hydrocarbyl group. Cyclopentadienyl-type as used herein are groups containing a cyclopentadienyl functionality, and include cyclopentadienyl, substituted cyclopentadienyl, indenyl, substituted indenyl, tetrahydroindenyl, fluorenyl, substituted fluorenyl, and octahydrofluorenyl groups. Cyclopentadienyl-type compounds are compounds containing a cyclopentadienyl-type group. The term alkynyl fulvene-type compound as defined herein is a fulvene-type compound containing a terminal alkynyl bond. As used herein, the term alkynyl ligand is a ligand containing a terminal alkynyl bond and at least one cyclopentadienyl-type group.
Cyclopentadienyl-type ligands have found a number of uses in the past. Such ligands have utility in the preparation of metallocene compounds useful for the polymerization of olefins. Other applications for metallocene compounds include asymmetric hydrogenation, alkene epoxidation, alkene isomerization, ketone reduction, and as stoichiometric reagents for stereoselective cobalt-mediated reactions, allyltitanium addition reactions with aldehydes, and the highly selective formation of allylic amines.
It would therefore be desirable to produce a variety of novel ligands from readily available materials employing a simple and economical process. It would also be desirable to produce a variety of such ligands in pure form without by-products and in high yields from readily available materials employing a simple and economical process.
Metallocene catalysts have been used in homogeneous solution polymerizations of olefins. Attempts to use soluble metallocene catalysts in a slurry or particle form type polymerization are currently not commercially feasible. It has been observed that when such particle form polymerizations are carried out in the presence of a soluble metallocene catalyst, large mounts of polymeric material are formed on the surfaces of the polymerization vessel. This surface fouling produces an adverse effect on the heat transfer and also results in the need for periodic, if not continuous, cleaning of the reactor. It would therefore be desirable to produce economical metallocene catalysts useful in polymerization processes free of reactor fouling.
For many applications, such as thermoforming, extrusion, blow molding and the production of film, it is desirable to produce a polymer having a broad molecular weight distribution. It would therefore be desirable to produce metallocene catalysts capable of producing polymers having a broad molecular weight distribution.